Honduran Edilberto Lanza Mejia and his family are released by Border Patrol at the McAllen bus station.

U.S. Border Patrol is overwhelmed by the numbers of children and families crossing the border with limited ability to process and hold those crossing illegally. (Johnny Hanson / Houston Chronicle)

Photo By Johnny Hanson

A group of seven people are smuggled Saturday from Mexico across the Rio Grande to Anzalduas County Park in Mission. The group from El Salvador and Honduras is made up of a mother with a 7-year-old son, another mother with a 4-year-old daughter, an 11-year-old boy and two 17-year-olds.

Photo By Johnny Hanson

A group of seven people are smuggled Saturday from Mexico across the Rio Grande to Anzalduas County Park in Mission. The group from El Salvador and Honduras is made up of a mother with a 7-year-old son, another mother with a 4-year-old daughter, an 11-year-old boy and two 17-year-olds.

McALLEN - A little before noon on Friday, a white Homeland Security bus stopped outside a public bus terminal in downtown McAllen, its doors opening to disgorge a group of about 20 immigrants from Central and South America.

A father carried a sleeping 9-month-old with curly black hair. A mother steered two toddlers toward the terminal.

"They just left us here," said Norma Navarro, from El Salvador, as the government bus pulled away from the terminal. "We have nothing."

But each person on the bus had at least one critical possession: a packet of U.S. government-issued documents ordering them to report to immigration officials within 15 days of landing at their new destination, and to appear in immigration court on a set date.

The paperwork confers no legal status, but many immigrants see it as a pass to a new life. Edilberto Lanza Mejia, a 26-year-old from Honduras holding his infant son, described it like this: "It is a permit to enter the United States."

The flow of Central and South Americans through South Texas has become an unmanageable torrent within the past month, overwhelming the Border Patrol, and the Office of Refugee Resettlement, which is charged with placing thousands of unaccompanied minors who have been arrested.

"We are being overwhelmed," said U.S. Border PatrolAgent Christopher Cabrera, vice president of National Border Patrol Council Local 3307. "We have groups of 70, 80, 90 people just walking up and turning themselves in. They're finding the first agent and saying take me in and let me have my walking papers.

"If we don't get some help soon, it's going to be disastrous," he said.

Perry also asked the administration eliminate policies that he described as encouraging illegal immigration - in particular releasing immigrants from custody with notices to appear in court and reuniting youths caught alone in the country illegally with family members in the U.S.

"I ask you to take action to prevent the situation along the U.S.-Mexico border from further escalating by providing more resources to secure our porous border," Perry wrote.

Top Department of Homeland Security officials said they already have dispatched hundreds more agents to the Texas border, and are in high-level talks with other agencies about how to reduce the flow of unaccompanied children through the Rio Grande Valley.

"This situation is an example of a broken immigration system and the need to fix our legal immigration channels to allow for immigrant families, in particular children and other vulnerable populations, to reunite legally and safely," department spokeswoman Marsha Catron said in a statement.

The steep influx of children and families in particular has caused turmoil within the agency, prompting some Homeland Security officials to agitate internally for a shift.

"We're not going to interdict our way out of this problem. More arrests just mean more problems," a Homeland Security official said. "We need a policy change so we can send these families and children back home instead of turning them loose."

But the argument is not as simple as some politicians or policymakers would make it seem, immigration experts said.

The U.S. government treats immigrants caught along the Southwest border differently, based on where they are from and if they need special protections dictated by federal law or lawsuit settlement agreements.

Most adults from Mexico caught near the border are typically processed and returned to the port of entry within days. Mexican children who claim a fear of returning home or indicate they have been trafficked are put into formal removal proceedings and transferred to the custody of the Office of Refugee Resettlement.

Adults from countries other than Mexico generally are held in Immigration and Customs Enforcement detention centers and placed in expedited removal proceedings, which allow the government to fast-track them for flights home without a court hearing.

But when immigrants from countries other than Mexico are caught with children, it becomes more complicated. Legally, the government can detain families pending their removal, but ICE officials have only one residential family detention center, located in Reading, Penn., with a capacity of 96.

So instead of being detained, most parents with young children are typically processed by the Border Patrol and ordered to report to ICE and appear in court, and taken to bus stations and released from custody.

Flood of children

One group of immigrants poses perhaps the greatest challenge for immigration officials: youths under 18 from countries other than Mexico caught in the U.S. illegally and alone.

Because they are considered particularly vulnerable, the law requires immigration officials to hand them over to the Office of Refugee Resettlement.

Once in ORR custody, the youths typically are housed in a sprawling network of state-licensed shelters and other facilities until the government can arrange for their release to relatives of other sponsors in the U.S. pending the outcome of their immigration cases.

Children are moving through the detention system at record pace because of the strain on the system, with about 90 percent released to a sponsor in the United States.

The flood of illegal immigration has caused major overcrowding at Border Patrol stations, severely overtaxing an agency and facilities designed to detain people for only a few hours.

Cabrera offered an example of the overcrowding: The Border Patrol station in McAllen is supposed to hold up to 270 people in the processing area. "Now you're looking at 1,000 to 1,200 there. And about 300 of them aren't even in a building. They're out in a garage."

The agency recently has resorted to sending buses full of adult Central and South American immigrants for processing to stations downriver - some all the way to Tucson, Ariz. The agency also started flights to Arizona, where illegal crossings have declined in recent years and more agents are available to help, a Homeland Security official said.

Busloads of immigrants from Central and South America caught crossing with young children are being issued notices to appear in immigration court and deposited at bus stations from South Texas to Arizona. At the McAllen bus station on Friday afternoon, government buses pulled up about every two hours.

"Where am I?" one woman asked after walking into the terminal with her immigration paperwork, a young boy in tow.

"The Border Patrol is doing a heroic job trying to address this issue, but they are overwhelmed," said Rep. Henry Cuellar, D-Texas. "What they are doing cannot be sustained."

Arrests in the Rio Grande Valley sector have topped more than 160,000 so far this fiscal year, eclipsing the total arrests in all of last year with months to go.

Strained system

Catron said in a statement that DHS Secretary Jeh Johnson has declared a "Level IV condition of readiness" because of the strain on the system caused by the numbers of unaccompanied children caught so far this year. Catron said DHS personnel from across the country have been reassigned to help with their processing and care.

Some 400 unaccompanied youths were detained in the Rio Grande Valley in a single day this week, DHS data show.

Unaccompanied children from countries other than Mexico are supposed to be turned over to ORR within 72 hours, but they are coming into the system faster than they can be processed and released, DHS officials said. That has created a logjam of more than 2,000 unaccompanied children in Border Patrol custody in the Rio Grande Valley as of Friday. About half of them were there for more than 72 hours, the official said.

ORR's detention system is also overwhelmed. Last month, it started temporarily housing about 1,200 unaccompanied children at Lackland Air Force Base in San Antonio. The agency also used a summer camp outside Waco to house hundreds more at a time.

Advocates said they were concerned that the strains on the system could lead to children missing out on legal orientations or screenings.

They also stressed that the children on the military base should have the same access to services as those in more permanent facilities. "There is no oversight of their conditions or their legal access," said David Walding, director of the Bernardo Kohler Center Inc., which provides legal services to unaccompanied children.

An ORR spokesman did not respond to questions about the specific services that children are being provided at the base.

Catron said federal officials are trying to figure out solutions to stem the flow and find more bed space.

"DHS and (Department of Health and Human Services) have been working closely together for some time to address the increased number of children, which has been an ongoing trend, but the tools at our disposal are limited," Catron said in the statement.

ORR officials estimate 60,000 unaccompanied children will land in their custody this year - more than nine times as many as in 2011.

Academics, advocates and government officials have struggled to pinpoint a cause for the steep influx. They cite a confluence of factors, including poverty, hopes of reuniting with relatives in the U.S. and a growing "humanitarian crisis" in Central and South America caused by destabilizing gang and cartel violence.

"I know a lot of people in Washington are asking questions about why people are coming, and what is the answer?" said Meredith Linsky, director of the South Texas Pro Bono Asylum Representation Project, which provides pro bono legal assistance to asylum seekers. "I don't think anyone really has the answer, but certainly conditions in Central America are going to have to improve in order for people to continue to live there, and live a dignified life."

'It doesn't work'

Catron said DHS is expanding awareness campaigns in Central and South America, and officials are trying to underscore the fact that people caught in the U.S. - including children trying to reunite with family members - are not eligible for legal status.

Michelle Brané, director of the Migrant Rights and Justice program for the Women's Refugee Commission, said the solution is not to start detaining families. She pointed to a family detention center in Taylor that closed down years ago amid protests over the detention conditions and the ethics of locking up children for long periods of time - even with their parents.

At the McAllen bus station, Lanza said he and his wife and three children - ages 9 months, 2 and 5 - were happy to be out of Honduras, and out of Border Patrol custody. They spent five days in a cold and cramped cell, sleeping on the concrete floor, he said. The baby developed a phlegmy cough.

"We should take him to a hospital," Lanza said. "Soon."

Within hours of arriving, Lanza borrowed a cellphone in the bus terminal. His wife called her sister in North Carolina, who paid for their fare to Greenville. They had tickets for the last bus out that night, leaving at 11:30.

Lanza smiled with relief, and settled into a seat inside the bus station to wait.

Just then, another white bus with a DHS logo pulled up outside the terminal and opened its doors.